Headrest

ABSTRACT

The objective of the present invention is to provide a headrest that can have increased comfort and safety. This headrest is provided with: an affixed-side member provided to a headrest pillar; a mobile-side member that is joined to the affixed-side member with a mobile mechanism therebetween and that can move in the front-back direction with respect to the affixed-side member; and a front-back locking mechanism that has an engaged section and a lock member that engages the engaged section, and that locks and unlocks the movement of the mobile-side member in the front-back direction. Also, the mobile-side member has a front-side cover for supporting a head. Furthermore, the engaged section is attached to the back surface of the front-side cover.

This is a continuation Application of application Ser. No. 14/758,282filed Jun. 29, 2015, issued as U.S. Pat. No. 9,815,392, which is a U.S.National Phase of PCT/JP2012/084168 filed Dec. 28, 2012. The disclosuresof the prior applications are hereby incorporated by reference herein inits entirety.

TECHNICAL FIELD

The present invention relates to a headrest.

BACKGROUND ART

A headrest of a vehicle seat is provided to improve the level of comfortand safety through the support of a head of a person who sits on theseat.

Patent Literature 1 discloses a headrest including a rear unit fixed toheadrest pillars, and a front unit that is connected to the rear unitwith a pair of X link members of a linkage and moves apart from the rearunit upon a rear-end collision. The movement of the front unit of theheadrest apart from the rear section is caused by an unlocking operationof a solenoid in response to the rear-end collision.

Such a headrest, which includes the X link members functioning asdiagonal supports, has sufficient strength against the stress of a headpushing back the front unit of the headrest.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent No. 4280589

SUMMARY OF INVENTION Technical Problem

The level of comfort and safety offered by the headrest of the seatdepends greatly on whether the headrest is at an appropriate positionwith respect to the head of the person who sits on the seat.

The headrest described in Patent Literature 1 has the front unit whichmoves only upon the rear-end collision. The position of the front unit(hereafter referred to as a movable-side member) of the headrest cannotbe adjusted in the front and back directions under normal conditions.The comfort and the safety offered by the headrest have been desired tobe compatible

An object of the present invention is to provide a headrest which canenhance the comfort and the safety.

Solution to Problems

In order to solve the above problems, various embodiments of a headrestincludes an affixed-side member which is arranged at a headrest pillar;a movable-side member which is connected to the affixed-side member viaa moving mechanism and which moves in front and back directions withrespect to the affixed-side member; and a front-back locking mechanismincluding a to-be-engaged unit and a lock member which engages with theto-be-engaged unit, the front-back locking mechanism locking andunlocking movement of the movable-side member in the front and backdirections, wherein the movable-side member includes a front cover whichsupports a head, and the to-be-engaged unit is attached on a backsurface of the front cover.

In various embodiments of the headrest, a plurality of the to-be-engagedunits are provided, and the plurality of the to-be-engaged units arearranged at position so that the moving mechanism is to be arrangedtherebetween.

In various embodiments of the headrest, the moving mechanism is formedin a linkage mechanism, the front cover includes supporting units whichrotatably support link members which constitute the linkage mechanism,and connecting members, which rotatably connect end parts of the linkmembers to the supporting units, are provided so as to penetrate theto-be-engaged unit, the link members and the supporting units.

In various embodiments of the headrest, the linkage mechanism is a Xlinkage mechanism including a first link member and a second link memberwhich are rotably connected via a center cross connection unit, and thesupporting units of the front cover are arranged on both sides of thefront cover in up and down directions, a front end of the first linkmember and a front end of the second link member are rotatably supportedby the upper and lower supporting units, and the connecting members areprovided so as to respectively penetrate the supporting units.

In various embodiments of the headrest, through holes in which theconnecting members go through are respectively formed at the upper andlower supporting units, one of the through holes of the upper and lowersupporting units is an elongated hole which is elongated in the up anddown directions, the to-be-engaged unit includes: a plurality of teethwhich are arranged in front and back directions; and upper and lowerattaching units which are attached to the front cover, through holes inwhich the connecting members go through being formed in the upper andlower attaching units, one of the through holes of the upper and lowerattachment units is an elongated hole which is elongated in the up anddown directions, and the one of the through holes of the attaching unitsand a tooth at very front among the plurality of teeth align in avertical direction.

In various embodiments of the headrest, the link members include aplurality of reinforcement units arranged at a plurality of parts of thelink members, and at least one of the plurality of reinforcement unitsis formed in a honeycomb structure.

In various embodiments of the headrest, the front cover includes areinforcement rib which is arranged on a back surface of the frontcover, and the reinforcement rib and the front end parts of the linkmembers are arranged on left and right sides of each other.

In various embodiments of the headrest, the headrest pillar includes apair of pillars, the affixed-side member includes: a pair of pillarholding units which are arranged on both side end parts of theaffixed-side member and which respectively hold the pillars of theheadrest pillar forming the pair; and a connector which connects betweenthe upper ends of the pillar holding units forming the pair.

In various embodiments of the headrest, a part of the affixed-sidemember which is surrounded by the pillar holding units forming the pairand the connector is a concave unit, and when the affixed-side memberand the movable-side member are close to each other, the movingmechanism is to be housed in the concave unit.

In various embodiments of the headrest, the to-be-engaged unit isprojected toward the affixed-side member from the back surface of thefront cover, a through hole is formed in the affixed-side member at aposition corresponding to the to-be-engaged unit, the to-be-engaged unitbeing inserted in the through hole, and a wall which faces theto-be-engaged unit is provided at a circumference of the through hole.

Advantageous Effects of Invention

According to various embodiments of the invention, the front-backpositional adjustment of the movable-side member using the to-be-engagedunits and supporting of the heat by the to-be-engaged units at the timecollision are compatible. Therefore, the level of comfort and securityof the seat when a passenger sits thereon can be improved.

According to various embodiments of the invention, since the pluralityof the to-be-engaged units are arranged at a plurality of parts havingthe moving mechanism therebetween, operation of the moving mechanism andthe front-back locking mechanism can be carried out in a good balance.Further, since the head can be supported by the plurality of theto-be-engaged units, the level of security can be improved.

According to various embodiments of the invention, since the connectingmembers are used to connect the to-be-engages units, the link membersand the supporting units and used as rotary shafts, the number of partsneeded can be reduced due to sharing the parts.

According to various embodiments of the invention, even if the parts tobe connected increase, they can be connected by the connecting members.Therefore, the effect of reduction in the number of parts due to sharingcan be improved even more.

According to various embodiments of the invention, the length in the upand down directions of the part near the upper end of the elongated holeof one of the attachment units can be made longer for the partcorresponding to the very front teeth. Therefore, rigidity of one of theattachment units can be improved.

According to various embodiments of the invention, by forming at leastone of the plurality of reinforcement units of the link member in thehoneycomb structure, the link member can be lightened and reinforced soas not to bend easily.

According to various embodiments of the invention, interference betweenthe reinforcement rib of the front cover and the front end part of thelink member can be prevented, and rigidity of the front cover can beimproved by the reinforcement rib.

According to various embodiments of the invention, the upper end partsof the pair of pillar holding units can be connected by the connector.Therefore, the connecting condition of the pillar holding units formingthe pair can be improved and rigidity of the affixed-side member can beimproved.

According to various embodiments of the invention, since the movingmechanism can be housed in the concave unit, the space between theaffixed-side member and the movable-side member can be used efficiently,and the headrest can be formed in a compact manner.

According to various embodiments of the invention, the projecting tipsof the to-be-engaged units which are inserted in the through holes areheld by the affixed-side member in which the through holes are formed.Further, since the to-be-engaged units can be supported by the wallswhich face the to-be-engaged units, stability of the movable-side memberat the time of front-back positional adjustment can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an inner mechanism of a headrest.

FIG. 2 is a perspective view showing a headrest in a state where a frontcover and a back cover are attached.

FIG. 3 is a perspective view showing a headrest in a state where theback cover is attached.

FIG. 4 is a perspective view showing the back surface side of the frontcover and a rotary operation member.

FIG. 5 is a perspective view showing the back surface side of the frontcover and a to-be-engaged unit.

FIG. 6 is a back view showing the inner structure and an operation unitof the headrest.

FIG. 7 is a cross-sectional view showing an inner structure of theheadrest.

FIG. 8 is a perspective view showing an inner structure of the headrestbefore movement.

FIG. 9 is a side view showing the inner structure of the headrest beforemovement.

FIG. 10 is a perspective view showing the inner structure of theheadrest after movement.

FIG. 11 is a side view showing the inner structure of the headrest aftermovement.

FIG. 12 is an enlarged front view showing a section near a through holeformed in an affixed-side member.

FIG. 13 is a perspective view showing the front surface side of the backcover.

FIG. 14 is an outline view showing another example of a biasing unit.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the present invention will be describedwith reference to the drawings.

As shown in FIGS. 1 to 11, a headrest 1 of the embodiment includes aheadrest pillar 2 having a pair of pillars 2 a and 2 b, a pair of holderunits 3 and 3, an affixed-side member 4, a moveable-side unit 5, amoving mechanism, a front-back locking mechanism, an up-down lockingmechanism and an operation unit 9. The headrest 1 further includes acushion pad and an outer layer material which are arranged around theheadrest 1.

The headrest 1 is attached to the upper end part of a seatback of avehicle seat.

Here, in the embodiment, the front, back, up, down, left and rightdirections comply with the direction of the vehicle seat and thevehicle.

The pair of holders 3 and 3 are to be attached to a seatback frame whichis the framework of the seatback.

The pair of pillars 2 a and 2 b of the headrest pillar 2 extend downwardfrom the headrest 1 and are held by the pair of holder units 3 and 3.That is, the headrest 1 is attached to the seatback frame via the pairof pillars 2 a and 2 b and the pair of holder units 3 and 3.

The pillars 2 a and 2 b forming a pair have the same diameter, and atleast one of the pillars 2 a and 2 b forming a pair has a plurality ofcutouts 15 along the length direction with spaces therebetween.

The pillars 2 a and 2 b forming a pair are respectively held by theholder units 3 and 3 forming a pair. The pillars 2 a and 2 b are movablein the up and down directions along the holder units 3 and 3 forming apair.

Each of the holder units 3 and 3 forming a pair includes a cylindricalmain body 3 a which holds either of the pillars 2 a and 2 b forming apair, a cover body 3 b which covers the cylindrical main body 3 a and ahead unit 3 c which is provided at the upper end part of the cylindricalmain body 3 a.

Further, each head unit 3 c includes a lock unit 3 d which preventseither of the pillars 2 a and 2 b forming a pair from slipping out byengaging with the plurality of cutouts 15 of either of the pillars 2 aand 2 b forming a pair.

The pillars 2 a and 2 b forming a pair include projecting units 2 c and2 c which slide freely along slits 20 a and 20 b of the after-mentionedaffixed-side member 4 in a state where the pillars 2 a and 2 b forming apair respectively being inserted in the pillar inserting holes 20 and 20of the after-mentioned affixed-side member 4. The projecting units 2 cand 2 c function as so-called rotation stoppers which prevent thepillars 2 a and 2 b forming a pair from rotating in the circumferentialdirection.

The projecting units 2 c and 2 c project more outward than the sidesurfaces of the affixed-side member 4.

With respect to the affixed-side member 4, the pillars 2 a and 2 bforming a pair are respectively arranged at the left and right end partsthereof. The affixed-side member 4 is to be attached to the seatbackframe via the pair of pillars 2 a and 2 b.

The affixed-side member 4 is movable in the up and down directions alongthe pair of pillars 2 a and 2 b.

The movable-side member 5 is movable in the front and back directionswith respect to the affixed-side member 4 and is connected with theaffixed-side member 4 via the moving mechanism. In particular, themoveable-side member 5 is connected with the affixed-side member 4 viathe moving mechanism and is movable in the front direction, which is thedirection parting from the affixed-side member 4, and in the backdirection, which is the direction returning toward the affixed-sidemember 4.

The moveable-side member 5 includes a front cover 30 and a back cover 31which can house individual parts including the affixed-side member 4,the moving mechanism, the upper parts of the pillars 2 a and 2 b forminga pair, etc.

The moving mechanism connects the affixed-side member 4 and themoveable-side member 5, and for example, a link mechanism is adopted. Inthe embodiment, in particular, an X linkage mechanism is adopted. The Xlinkage mechanism includes a first link member 6 (hereinafter, aninner-side link member 6) and a second link member 7 (hereinafter, anouter-side link member 7) which are connected to each other so as torotate via a center cross connection unit 8.

The front-back locking mechanism locks and unlocks the movement of themoveable-side member 5 in the front and back directions with respect tothe affixed-side member 4. The front-back locking mechanism includesto-be-engaged units 10, a locking member 11 which engages with theto-be-engaged units 10, biasing units 12 which bias the locking member11 toward the to-be-engaged units 10 and a rotary operation member 13which is held by the moveable-side member 5 so as to rotate freely andwhich operates the locking member 11.

The up-down locking mechanism locks and unlocks the affixed-side member4 with respect to the pair of pillars 2 a and 2 b at any of theplurality of positions in the up and down directions. The up-downlocking mechanism includes the after-mentioned up-down locking member14.

The operation unit 9 is exposed from the outer surface of the headrest 1and is for operating the front-back locking mechanism and the up-downlocking mechanism at the same time. In particular, via the rotaryoperation member 13, operations to unlock the locked state of themoveable-side member 5 wherein the moveable-side member 5 is preventedfrom moving in the front and back directions and operation to unlock thelocked state of the affixed-side member 4 wherein the affixed-sidemember 4 is prevented from moving in the up and down directions arecarried out.

The operating direction of the operation unit 9 is along the widthdirection in the right and left directions. Operation of the operationunit 9 itself is carried out manually or automatically. In theembodiment, an embodiment of manual operation is adopted.

The operation unit 9 of the embodiment is a button 9 which is pushedinside the headrest 1 to operate the front-back locking mechanism andthe up-down locking mechanism.

Next, the affixed-side member 4, the moveable-side member 5 and the Xlinkage mechanism will be described in detail.

(Affixed-Side Member)

The affixed-side member 4 is made of resin. As shown in FIGS. 1 and 6,for example, the affixed-side member 4 is formed in a block shape andincludes a pair of pillar holding units 4 a and 4 b, aback sideconnector 4 c, a connector 4 d, a plurality of supporting units 25 and26, a plurality of reinforcement units 27 . . . and a lock holding unit28. With respect to the affixed-side member 4, all parts are formedintegrally.

The pillar holding units 4 a and 4 b forming a pair are arranged at theright and left end parts of the affixed-side member 4, the pillarholding units 4 a and 4 b constituting the right and left sides of theaffixed-side member 4. The pillar holding units 4 a and 4 b forming apair respectively hold the pillars 2 a and 2 b forming a pair. By havingsuch configuration, the affixed-side member 4 is movable in the up anddown directions along the pair of pillars 2 a and 2 b.

The pillar holding units 4 a and 4 b forming a pair respectively havepillar insertion holes 20 and 20 which bore through the pillar holdingunits 4 a and 4 b forming a pair in their length direction (up and downdirections), and the pillars 2 a and 2 b forming a pair are to beinserted therein.

On both sides of the affixed-side member 4, that is, on side surfaces ofthe pillar holding units 4 a and 4 b forming a pair, slits 20 a and 20 awhich communicate with the pillar insertion holes 20 and 20 arerespectively formed along the up and down directions.

The projecting units 2 c and 2 c of the pillars 2 a and 2 b forming apair are to be arranged in the slits 20 a and 20 a, respectively.

The back side connector 4 c is arranged between the pillar holding units4 a and 4 b forming a pair and is a board-like member which connects thepillar holding units 4 a and 4 b forming a pair. The back surface of theback side connector 4 c is flush with the back surfaces of the pillarholding units 4 a and 4 b forming a pair.

On the back surface of the back side connector 4 c, a holding unit 21which holds a to-be-held unit 70 of the after-mentioned lock member 11is arranged. The holding unit 21 has an upward hook-like shape when seenfrom a side and is formed in an elongated shape along the right and leftdirections of the back side connector 4 c.

The connector 4 d is arranged between the upper end parts of the pillarholding units 4 a and 4 b forming a pair and is formed in a board-likebody that connects between the upper end parts of the pillar holdingunits 4 a and 4 b forming a pair. The upper surface of the connector 4 dis flush with the upper surfaces of the pillar holding units 4 a and 4 bforming a pair.

The part of the affixed-side member 4 where surrounded by the pair ofpillar holding units 4 a and 4 b and the connector 4 d is a concave unit22 which is formed in a concave shape. In particular, the concave unit22 is the space between the surfaces of the pillar holding units 4 a and4 b forming a pair that face each other, front side of the back sideconnector 4 c and under the connector 4 d.

As shown in FIG. 3, the moving mechanism is to be housed in the concaveunit 22 in a state where the affixed-side member 4 and the movable-sidemember 5 are close to each other.

As shown in FIGS. 6, 8 and 10, the back side connector 4 c has throughholes 23 a and 23 b at positions corresponding to first protruding units60 and second protruding units 61 (will be described later) of theto-be-engaged units 10 constituting the front-back locking mechanism,and the first protruding units 60 and the second protruding units 61 arerespectively inserted in the through holes 23 a and 23 b.

As shown in FIG. 12, walls 24 a and 24 b facing the first protrudingunits 60 and the second protruding units 61 are arranged around thecircumferences of the through holes 23 a and 23 b. The walls 24 a arearranged between the through holes 23 a and 23 b and the walls 24 b arearranged so as to face the surfaces of the pair of pillar holding units4 a and 4 b that are facing each other. The surfaces of the pair ofpillar holding units 4 a and 4 b that are facing each other also has thefunction similar as that of the walls 24 a and 24 b.

A plurality of supporting units 25 and 26 are connected with theinner-side link member 6 and the outer-side link member 7 whichconstitute the X linkage mechanism so that the inner-side link member 6and the outer-side link member 7 rotate, and the plurality of supportingunits 25 and 26 support the inner-side link member 6 and the outer-sidelink member 7.

The plurality of supporting units 25 and 26 are respectively arranged atthe upper sides and the lower sides of the surfaces of the pair ofpillar holding units 4 a and 4 b that are facing each other. That is,the plurality of supporting units 25 and 26 are respectively arranged atthe four corners of the concave unit 22.

The supporting units 25 and 25 which are arranged at the upper side areformed integrally with the pair of pillar holding units 4 a and 4 b, theback side connector 4 c and the connector 4 d. The supporting units 26and 26 which are arranged at the lower side are formed integrally withthe pair of pillar holding units 4 a and 4 b and the back side connector4 c.

The plurality of upper side supporting units 25 and 25 respectively havethrough holes 25 a in which a connecting member S is to be inserted, thethrough holes 25 a being formed so as to penetrate the pair of pillarholding units 4 a and 4 b from the surfaces of the plurality ofsupporting units 25 on the concave unit 22 side. The through holes 25 aof the plurality of upper side supporting units 25 and 25 are roundholes.

The connecting member S is inserted in the round hole 25 a which isopened on the side of the pillar holding unit 4 a (4 b) which is one ofthe pair of pillar holding units 4 a and 4 b so as to connected the linkmember 6 (7).

The connecting members S connect the inner-side link member 6 and theouter-side link member 7 to the plurality of supporting units 25 and 26so as to rotate. In the embodiment, metallic shafts (rotary shafts) areused. That is, the connecting member S is arranged so as to go throughthe link member 6 (7) and the supporting units 25 and 25.

The plurality of lower side supporting units 26 and 26 are formed to belonger in the up and down directions comparing to the plurality of upperside supporting units 25 and 25.

The plurality of supporting units 26 and 26 respectively have throughholes 26 a in which a connecting member S is to be inserted, the throughholes 26 a being formed on the surfaces of the plurality of supportingunits 26 and 26 in the concave unit 22 side. The holes 26 a of theplurality of lower side supporting units 26 and 26 are elongated holes(slits) which are elongated in the up and down directions along theplurality of lower side supporting units 26 and 26.

Parts 26 b of the elongated holes 26 a are formed so as to penetrate thepillar holding units 4 a and 4 b forming a pair. The parts 26 b of theelongated holes 26 a are round holes. The connecting member S isinserted from the part 26 b of the elongated hole 26 a which opens on aside of the pillar holding unit 4 a (4 b) which is one of the pillarholding units 4 a and 4 b forming a pair so as to connect the linkmember 7 (6). The connecting member S is arranged so as to go throughthe link member 7 (6) and the supporting units 26 and 26.

The plurality of reinforcement units 27 . . . are arranged at aplurality of parts in the affixed-side member 4. Among the plurality ofreinforcement units 27, at least one is formed in a honeycomb structure.

In the embodiment, the front surfaces and the back surfaces of thepillar holding units 4 a and 4 b forming a pair are the reinforcementunits 27 having the honeycomb structure. By forming at least one of theplurality of the reinforcement units 27 of the affixed-side member 4 inthe honeycomb structure, the affixed-side member 4 can be lighter andcan be reinforced so that it is not easily bent.

Although it is not the honeycomb structure, a reinforcement unit 27 isalso formed in the upper surface of the connector 4 d. The reinforcementunit 27 of the connector 4 d has ribs arranged in a grid pattern.

The lock holding units 28 hold the up-down locking member 14 whichconstitutes the up-down locking mechanism and are respectively arrangednear the lower ends of the pillar holding units 4 a and 4 b forming apair. The up-down locking member 14 is provided at either one of thepillar holding units 4 a and 4 b forming a pair. In the embodiment, theup-down locking member 14 is arranged on the left side of the headrest1.

The lock holding unit 28 has an opening 28 a formed on a side and theup-down locking member 14 is provided through the opening 28 a.

With respect to the lock holding unit 28 on the side which the up-downlocking member 14 is not provided, the pillar 2 b (2 a) can be seenthrough the opening 28 a on the side.

Further, the lock holding units 28 are provided with catch units 28 b towhich the hook units 12 a of the biasing units 12 (after-mentioned) areto be hooked. The catch units 28 b of the embodiment are hole unitswhich are formed in the under surface of the front parts of the lockholding units 28.

(Movable-Side Member)

The movable-side member 5 is arranged on the side of the passenger'shead and can be moved in the front and back directions with respect tothe affixed-side member. In particular, as shown in FIGS. 2 to 5 andFIGS. 7 to 11, the movable-side member 5 is movable in the front andback with respect to the affixed-side member 4.

The movable-side member 5 is made of resin. The movable-side member 5includes a front cover 30, a back cover 31, lower edge covers 32 and 32,a holding unit 33, a button attaching unit 34, a plurality of supportingunits 35 and 36, a reinforcement rib 37 and concave units 38 and 38.With respect to the movable-side member 5, the front cover 30, the backcover 31 and the lower edge covers 32 and 32 are formed separately.

By assembling the front cover 30 and the back cover 31, a hollow casebody can be formed.

The front cover 30 is provided to support the head. The front cover 30includes a front side unit 30 a and a surrounding unit 30 b which isprovided toward the back from the surrounding edges (up, down, left andright) of the front side unit 30 a. The parts constituting the frontcover 30 are formed integrally.

As shown in FIGS. 4 and 5, ribs for reinforcing the boundary parts ofthe front side unit 30 a and the surrounding unit 30 b are arranged asneeded between the back side of the front side unit 30 a and thesurrounding unit 30 b.

The back cover 31 includes a back side unit 31 a and a surrounding unit31 b which is provided toward the front from the surrounding edges (up,down, left and right) of the back side unit 31 a. The case body isconstituted by connecting and fixating the surrounding unit 31 b of theback cover 31 and the surrounding unit 30 b of the front cover 30together.

By adapting a fitting mechanism, the surrounding unit 30 b and thesurrounding unit 31 b are connected by being fitted to each other.However, this is not limitative in anyway. Any known technique can beadopted.

As shown in FIG. 13, the back cover 31 is arranged at the positioncorresponding to the tips of the first protruding units 60 and the tipsof the second protruding units 61 of the to-be-engaged unit 10(after-mentioned), and the back cover 31 is provided with tip housingunits 31 d and 31 d in which the above mentioned tips are to be housed.

The tip housing units 31 d and 31 d are formed so as to protrude fromthe front surface of the back cover 31. The tip housing units 31 d and31 d respectively includes wall units 31 e which surround the tips ofthe first protruding units 60 and the tips of the second protrudingunits 61 and slits 31 f which prevent the to-be-held units 70 of thelock member 11 (after-mentioned) from interfering with the wall units 31e.

The lower edge covers 32 and 32 are respectively fitted to the twoelongated holes (will be described later) which are formed in the lowersurface of the case body which is formed by connecting the front cover30 and the back cover 31. Each lower edge cover 32 includes acylindrical unit 32 a which is to be inserted in an elongated hole and acollar unit 32 b which is arranged at the lower edge unit of thecylindrical unit 32 a and abuts the lower surface of the case body.

The lower surfaces of the surrounding unit 30 b and the surrounding unit31 b include cutouts units 30 c and 31 c for inserting the pair ofpillars 2 a and 2 b and the lower edge covers 32 and 32. Each of thecutout units 30 c and 31 c is formed in a shape where an elongated holeis cut in half. Elongated holes are to be formed in the lower surface ofthe case body by the surrounding unit 30 b and the surrounding unit 31 bbeing connected to each other.

Two elongated holes are formed in the lower surface of the case body,and the elongated holes are arranged so that they are elongated alongthe front-to-back moving direction of the movable-side member 5. Thecylindrical units 32 a are also arranged so that they are elongatedalong the front-to-back moving direction of the movable-side member 5.

The holding unit 33 is for holding the rotary shaft unit 82 of therotary operation member 13 (after-mentioned). As shown in FIGS. 4 and 5,the holding unit 33 is provided inside (in the inside space of the casebody) the surrounding unit 30 b of the front cover 30 on either left orright side thereof.

The holding unit 33 includes a plurality of upper abutting units 33 awhich abut the rotary shaft unit 82 from above and a lower abutting unit33 b which abuts the rotary shaft unit 82 from below. The upper abuttingunits 33 a include a plurality of claw units 33 c and 33 c which are thetip parts of the upper abutting units 33 a.

The upper abutting units 33 a and the lower abutting unit 33 b areformed so as to protrude toward the back cover 31 side from the frontcover 30 side.

As shown in FIGS. 2 to 5, the button attaching unit 34 is for attachingthe button 9 which is the operation unit 9 to the front cover 30 and theback cover 31. The button attaching unit 34 is arranged at one side ofthe front cover 30 and the back cover 31.

The button attaching unit 34 is a cylindrical body which protrudes froma side of the front cover 30 and the back cover 31. The button attachingunit 34 includes a cylindrical front unit 34 a which is arranged on thefront cover 30 side, a cylindrical back unit 34 b which is arranged onthe back cover 31 side and a ring-shaped button holding unit 34 c whichis arranged inside the front cover 30 and holds the button 9.

The button 9 is to be surrounded by the cylindrical front unit 34 a ofthe front cover 30 and the cylindrical back unit 34 b of the back cover31 in a state where the button 9 is being held by the button holdingunit 34 c. In such way, the button 9 is attached to the button attachingunit 34.

To the plurality of supporting units 35 and 36, the inner-side linkmember 6 and the outer-side link member 7 which constitute the X linkagemechanism are connected so as to rotate. The plurality of supportingunits 35 and 36 support the inner-side link member 6 and the outer-sidelink member 7.

The plurality of supporting units 35 and 36 are arranged at thepositions in the back surface of the front cover 30 corresponding to thefront edges of the inner-side link member 6 and the outer-side linkmember 7. The plurality of supporting units 35 and 36 are arranged onboth sides in the left and right directions (width) and both sides ofthe up and down directions on the back surface of the front cover 30.That is, the plurality of supporting units 35 and 36 are arranged at thefour positions on the back surface of the front cover 30.

The front edges of the outer-side link member 7 are connected to thesupporting units 35 and 35 which are arranged at the upper side and thefront edges of the inner-side link member 6 are connected to thesupporting units 36 and 36 which are arranged at the lower side.

On the surfaces of the plurality of supporting units 35 and 35 on theupper side that face each other, protruding units 35 b and 35 b whichprotrude toward the surfaces facing each other are respectively formedintegrally. The protruding units 35 b are for attaching theto-be-engaged unit 10 to the supporting units 35, and the protrudingunits 35 b are to be engaged with the through holes 63 a of theto-be-engaged unit 10 (after-mentioned).

The outside diameter of the protruding units 35 b is set to be slightlysmaller than the inside diameter of the through holes 63 a and is set tobe smaller than the diameter of the edges of the surfaces of thesupporting units 35 which face each other.

On the surfaces of the plurality of lower side supporting units 36 and36 that face each other, protruding units 36 b and 36 b which protrudetoward the surfaces facing each other are respectively formedintegrally. The protruding units 36 b are for attaching theto-be-engaged unit 10 to the supporting units 36, and the protrudingunits 36 b are to be engaged with the through holes 64 a of theto-be-engaged unit 10 (after-mentioned).

The outside diameter of the protruding units 36 b is set to be slightlysmaller than the inside diameter of the through holes 64 a and is set tobe smaller than the diameter of the edges of the surfaces of thesupporting units 36 which face each other.

In the plurality of upper side supporting units 35 and 35 and theprotruding units 35 b and 35 b, through holes 35 a in which theconnecting member S is to be inserted are formed so as to penetrate inthe left and right directions (width). Here, the through holes 35 a ofthe plurality of upper side supporting units 35 and 35 are round holes.

On the left and right surfaces of the surrounding unit 30 b of the frontcover 30, through holes 30 d and 30 d are respectively formed at thepositions on the lines extending from the through holes 35 a and 35 a ofthe plurality of upper side supporting units 35 and 35.

The connecting member S is inserted through the through holes 35 a ofthe plurality of supporting units 35 and 35 and the protruding unit 35 band 35 b from either one of the through holes 30 d in the left and rightside surfaces of the front cover 30 so as to connect the link member 7(6) to the plurality of supporting units 35 and 35. That is, theconnecting member S is arranged so as to go through the link member 7(6), the supporting units 35 and 35 and the to-be-engaged units 10 and10 which are attached to the supporting units 35 and 35.

The plurality of supporting units 36 and 36 and the protruding units 36b and 36 b on the lower side are formed in elongated shapes elongated inthe up and down directions comparing to the plurality of supportingunits 35 and 35 and the protruding units 35 b and 35 b on the upperside.

In the plurality of lower side supporting units 36 and 36 and theprotruding units 36 b and 36 b, the through holes 36 a in which theconnecting member S (after-mentioned) is to be inserted is formed so asto penetrate in the left and right directions (width). Here, the throughholes 36 a of the plurality of upper side supporting units 36 and 36 andthe protruding units 36 b and 36 b are elongated holes elongated in theup and down directions along the supporting units 36 and 36.

On the left and right surfaces of the surrounding unit 30 b of the frontcover 30, through holes 30 e and 30 e are respectively formed at thepositions on the lines extending from the elongated through holes 36 aand 36 a of the plurality of lower side supporting units 36 and 36. Thethrough holes 30 e and 30 e are round holes arranged on the linesextending from the upper edges of the elongated through holes 36 a and36 a.

The connecting member S is inserted through the through holes 36 a ofthe plurality of supporting units 36 and 36 and the protruding unit 36 band 36 b from either one of the through holes 30 e on the left and rightside surfaces of the front cover 30 so as to connect the link member 6(7) to the plurality of supporting units 36 and 36. That is, theconnecting member S is arranged so as to go through the link member 6(7), the supporting units 36 and 36 and the to-be-engaged units 10 and10 which are attached to the supporting units 36 and 36.

The reinforcement rib 37 is formed on the back surface of the frontcover 30 at the center position between the plurality of supportingunits 36 and 36.

The reinforcement rib 37 is formed so as to project toward the back, andthe degree of its projection is set so as not to interfere with theconnecting member S which is arranged at the plurality of the supportingunits 36 and 36.

The part in the front surface of the front cover 30 corresponding to thepart where the reinforcement rib 37 is formed is concaved correspondingto the projection of the reinforcement rib 37.

The reinforcement rib 37 and the front edges of the link (the inner-sidelink member 6 in the embodiment) are arranged in a line in the left andright sides of each other. That is, the reinforcement rib 37 is to bearranged between a first arm 40 and a second arm 41 of the inner-sidelink member 6 (after-mentioned).

The concave units 38 and 38 are formed on the back surface of the frontcover 30 at position corresponding to frontward protruding units 65 and65 of the to-be-engaged units 10 and 10 (after-mentioned).

The concave units 38 and 38 are arranged right above the plurality oflower side supporting units 36 and 36. At the outer edges of the concaveunits 38 and 38, the reinforcement ribs 38 a and 38 a are respectivelyformed integrally with the plurality of supporting units 36 and 36. Thereinforcement ribs 38 a and 38 a are respectively facing the front sideprotruding units 65 and 65 of the to-be-engaged units 10 and 10.

(X Linkage Mechanism)

As shown in FIGS. 1, 3, 7 to 11, in the X linkage mechanism, theinner-side link member 6 is a link in which the upper edge (back edge)thereof is arranged on the affixed-side member 4 side and the lower edge(front edge) thereof is arranged on the movable-side member 5 side.

The outer-side link member 7 is a link in which the upper edge (frontedge) thereof is arranged on the movable-side member 5 side and thelower edge (back edge) thereof is arranged on the affixed-side member 4side.

The front and back directions of the inner-side link member 6 and theouter-side link member 7 can be reversed. The X linkage mechanism ismade of resin except for the connecting member S.

The upper edge of the inner-side link member 6 is to be arranged betweenthe plurality of upper side supporting units 25 and 25 which arearranged at the left and right sides in the affixed-side member 4.

The lower edge of the outer-side link member 7 is arranged between theplurality of lower side supporting units 26 and 26 which are arranged atthe left and right sides in the affixed-side member 4.

The lower edge of the inner-side link member 6 is arranged between theplurality of lower side supporting units 36 and 36 which are arranged atthe left and right sides in the movable-side member 5.

The upper edge of the outer-side link member 7 is arranged between theplurality of upper side supporting units 35 and 35 which are arranged atthe left and right sides of the movable-side member 5.

As shown in FIG. 7, the inner-side link member 6 and the outer-side linkmember 7 are in a bent shape when seen from a side.

The inner-side link member 6 and the outer-side link member 7 areconnected via the center cross connection unit 8 so as to rotate.

In the X linkage mechanism, a part where one link and the other linkoverlap is naturally formed. Therefore, the cross connection unit 8 isarranged at the part where the inner-side link member 6 and theouter-side link member 7 overlap with each other, the overlapping partbeing naturally formed when constituting the X linkage mechanism.

The cross connection unit 8 is arranged on the line connecting theconnecting members S and S respectively arranged at the upper edge andthe lower edge of the inner-side link member 6 and on the lineconnecting the connecting members S and S respectively arranged at theupper edge and the lower edge of the outer-side link member 7.

In the inner-side link member 6 and the outer-side link member 7, roundholes which penetrate the inner-side link member 6 and the outer-sidelink member 7 are respectively formed at the parts corresponding to thecross connecting unit 8. A connecting member S is inserted in the roundholes. That is, the inner-side link member 6 and the outer-side linkmember 7 are connected to each other so as to rotate with the connectingmember S being the rotary shaft.

The inner-side link member 6 of the embodiment includes the first arm 40and the second arm 41. That is, the two arms 40 and 41 constitute theinner-side link member 6 of the embodiment. The inner-side link member 6further includes a plurality of connections 42 which are arranged at theedge parts of the first arm 40 and the second arm 41.

The first arm 40 and the second arm 41 are formed so to be symmetricaland are arranged to face the same direction having a space between eachother. The inside unit 51 of the outer-side link member 7 is arranged inthe space between the first arm 40 and the second arm 41.

The first arm 40 includes reinforcement units 43 at both the left andright sides thereof and the second arm 41 includes reinforcement units44 at both the left and right sides thereof. These reinforcement units43 and 44 are not the honeycomb structure. The reinforcement units 43and 44 have a plurality of ribs arranged therein.

The plurality of connections 42 . . . are the upper and lower edges ofthe first arm 40 and the second arm 41, and are the parts connected tothe upper side supporting units 25 and 25 of the affixed-side member 4and the lower side supporting units 36 and 36 of the movable-side member5 and supported by the upper side supporting units 25 and 25 and thelower side supporting units 36 and 36.

Through holes are formed in the connections 42 and 42 at the upper edgesof the first arm 40 and the second arm 41 so as to penetrate theconnections 42 and 42, in which the connecting member S is to beinserted, in the left and right directions (width). The through holesare round holes.

Since the connecting members S is to be inserted in the through holes,the through holes are arranged on the line extending from the throughholes 25 a and 25 a that are formed in the plurality of upper sidesupporting units 25 and 25 of the affixed-side member 4. The connectingmember S is inserted in the round holes of the upper side supportingunits 25 and 25 and the round holes of the connections 42 and 42 at theupper edges. That is, the first arm 40 and the second arm 41 areconnected to the affixed-side member 4 via the connecting member S so asto rotate, the connecting member S being the rotary shaft.

Similarly, through holes (round holes) are formed in the connections 42and 42 at the lower edge parts of the first arm 40 and the second arm41.

The connecting member S is inserted in the plurality of the elongatedholes 36 a and 36 a of the plurality of lower side supporting units 36and 36 of the movable-side member 5 and the round holes of theconnections 42 and 42 at the lower edges. That is, the first arm 40 andthe second arm 41 are connected to the movable-member 5 via theconnecting member S so as to rotate, the connecting member S being therotary shaft.

The connecting member S arranged at the connections 42 and 42 at thelower edges of the first arm 40 and the second arm 41 can move in the upand down directions along the elongated holes 36 a and 36 a formed inthe plurality of lower side supporting units 36 and 36. That is, thelower edges of the first arm 40 and the second arm 41 can move in the upand down directions along the lower side supporting units 36 and 36according to the front-to-back movement of the movable-side member 5.

The reinforcement rib 37 is arranged between the connection 42 at thelower edge of the first arm 40 and the connection 42 at the lower edgeof the second arm 41.

The outer-side link member 7 of the embodiment includes left and rightside wall units 50 and 50, an inside unit 51 arranged between the leftand right side wall units 50 and 50, a plurality of connections 52 . . .and a plurality of reinforcement units 53 . . . . The left and rightside wall units 50 and 50, the inside unit 51, the plurality ofconnections 52 and 52 and the plurality of reinforcement units 53 . . .are formed integrally.

The left and right side wall units 50 and 50 are the parts positioningoutside of the first arm 40 and the second arm 41 of the inner-side linkmember 6. The left and right side wall units 50 and 50 are arranged soas to intersect with the first arm 40 and the second arm 41 and sandwichthe first arm 40 and the second arm 41.

The inside unit 51 is the part that intersects with the first arm 40 andthe second arm 41 of the inner-side link member 6 and sandwiched by theleft and right side wall units 50 and 50.

At the part of the inside unit 51 where intersects with the first arm 40and the second arm 41, arm inserting holes 51 a and 51 a in which thefirst arm 40 and the second arm 41 are to be inserted are formed.

The arm inserting holes 51 a and 51 a are formed in a size in which theinside unit 51 does not interfere with the first arm 40 and the secondarm 41 when the inner-side link member 6 and the outer-side link member7 are folded.

When the movable-side member 5 is returned to the affixed-side member 4side, the inside unit 51 abuts the first arm 40 and the second arm 41.The parts of the inside unit 51 where abut the first arm 40 and thesecond arm 41 are formed in a concaved shape (concave units 51 b). Whenthe movable-side member 5 is returned to the affixed-side member 4 side,the first arm 40 and the second arm 41 are to be housed in the concaveunits 51 b of the inside unit 51. In such way, the inner-side linkmember 6 and the outer-side link member 7 can be folded in a compactmanner.

The concave units 51 b are formed respectively at the upper left andright edges of the inside unit 51 on its back surface and at the lowerleft and right edges of the inside unit 51 on its front surface.

The plurality of connections 52 and 52 are the upper and lower edges ofthe outer-side link member 7 and are the parts that are connected to thelower side supporting units 26 and 26 of the affixed-side member 4 andthe upper side supporting units 35 and 35 of the movable-side member 5and supported by the lower side supporting units 26 and the upper sidesupporting unit 35 and 35.

Through holes in which the connecting member S is to be inserted areformed in the connections 52 and 52 so as to penetrate the connections52 and 52 in the left and right directions (width). The through holesare round holes.

The connecting member S is to be inserted in the through holes.Therefore, the through holes are respectively formed on the lineextending from the through holes 26 a and 26 a which are formed in theplurality of lower side supporting units 26 and 26 of the affixed-sidemember 4 and on the line extending from the through holes 35 a and 35 awhich are formed in the plurality of upper side supporting units 35 and35 of the movable-side member 5.

The connecting member S is inserted in the elongated holes of the lowerside supporting units 26 and 26 and the round holes of the connections52 at the lower edges.

The connecting member S which is arranged in the connections 52 at thelower edges can move in the up and down directions along the elongatedholes 26 a and 26 a which are formed in the plurality of lower sidesupporting units 26 and 26. That is, the lower edge of the outer-sidelink member 7 can move in the up and down directions along the lowerside supporting units 26 and 26 according to the front-to-back movementof the movable-side member 5.

The connecting member S is inserted in the round holes of the upper sidesupporting units 35 and 35 and the round holes of the connections 52 atthe upper edges. That is, the upper edge of the outer-side link member 7is connected to the movable-side member 5 via the connecting member S soas to rotate, the connecting member S being the rotary shaft.

The plurality of reinforcement units 53 are arranged at a plurality ofparts in the outer-side link member 7, and at least one of the pluralityof reinforcement units 53 is formed in the honeycomb structure.

In the embodiment, the plurality of reinforcement units 53 are arrangedon the side of the outer-side link member 7 which is the opposite sideof the side on which the concave units 51 b are formed, that is, theplurality of reinforcement units 53 are arranged at the upper left andright edges on the front surface of the inside unit 51 and at the lowerleft and right edges on the back surface of the inside unit 51. In theinside unit 51, the reinforcement units 53 are provided on the backsurface and the front surface at the upper sections of the partpositioning between the first arm 40 and the second arm 41 of theinner-side link member 6.

In the embodiment, all of the reinforcement units 53 have the honeycombstructure.

By adapting the above described configuration, the movable-side member 5can be moved so as to apart from the affixed-side member 4 in theforward direction and so as to approach the affixed-side member 4 in thebackward direction via the X linkage mechanism which is the movingmechanism.

Next, the front-back locking mechanism and the up-down locking mechanismwill be described in detail.

(Front-Back Locking Mechanism)

As described above, the front-back locking mechanism includes theto-be-engaged units 10, the locking member 11 which engages with theto-be-engaged units 10, the biasing units 12 which bias the lockingmember 11 toward the to-be-engaged units 10, and the rotary operationmember 13 which operates the locking member 11, the rotary operationmember 13 being held at the movable-side member 5 so as to rotatefreely.

The to-be-engaged units 10 are made from metal, and as shown in FIGS. 1,3 and 5, for example, the to-be-engaged units 10 are attached on theback surface of the front cover 30 and protrude toward the affixed-sidemember 4 from the back surface of the front cover 30.

A plurality of to-be-engaged units 10 are used and they are arranged soas to have the X linkage mechanism between them.

Each of the to-be-engaged units 10 has the ratchet mechanism having aplurality of teeth 60 a which are arranged in a line in the front andback directions. The plurality of teeth 60 a are projected upward frombelow.

Each to-be-engaged unit 10 includes the first protruding unit 60, thesecond protruding unit 61, a space 62, attachment units 63 and 64 andthe frontward protruding unit 65.

Each to-be-engaged unit 10 is formed in an approximately T-shape whenseen from a side. That is, the first protruding unit 60 and the secondprotruding unit 61 are protruded in an approximately horizontaldirection. The attachment unit 63 projects upward in approximatelyvertical direction and the attachment unit 64 projects downward inapproximately vertical direction.

Each of the first protruding units 60 has a plurality of teeth 60 a, andthe to-be-engaged unit 10 is projected toward the affixed-side member 4from the movable-side member 5 in a state being attached to the backsurface of the front cover 30.

Each of the first protruding units 60 is arranged below the plurality ofteeth 60 a since the plurality of teeth 60 a . . . which project upwardfrom below are formed thereon. That is, the plurality of teeth 60 a areformed so as to project upward from the upper edges of the firstprotruding units 60.

The tips of the first protruding units 60 are formed to have a tapershape and are to be housed in the tip housing units 31 d of the backcover 31.

The second protruding units 61 are parallel to the first protrudingunits 60, respectively, and are arranged so as to have spaces betweenthe upper edges of the plurality of teeth 60 a. The spaces between thesecond protruding units 61 and the plurality of teeth 60 a of the firstprotruding units 60 are the spaces 62.

The tips of the second protruding units 61 are to be housed in the tiphousing units 31 d of the back cover 31.

The through holes 63 a and 64 a in which the connecting members S are tobe inserted are formed in the attachment units 63 and 64 and theattachment units 63 and 64 are attached to the front cover 30.

The attachment units 63 are formed so as to protrude upward from thebase parts (front) of the second protruding units 61 and the attachmentunits 64 are formed so as to protrude downward from the base parts(front) of the first protruding units 60.

As described above, the through holes 63 a are where the protrudingunits 35 b and 35 b of the plurality of upper side supporting units 35and 35 are to be fitted, respectively. That is, by fitting the throughholes 63 a and the protruding units 35 b, respectively, the attachmentunits 63 can be attached to the back surface of the front cover 30.

Each attachment unit 63 has a slit 63 b formed below the through hole 63a. The slits 63 b contribute to lightening of the to-be-engaged unit 10.

As described above, the through holes 64 a are where the protrudingunits 36 b and 36 b of the plurality of lower side supporting units 36and 36 are to be fitted, respectively. That is, by fitting the throughholes 64 a and the protruding units 36 b, respectively, the attachmentunits 64 can be attached to the back surface of the front cover 30.

The through holes 64 a are elongated holes which are elongated in the upand down directions corresponding to the shapes of the supporting units36 and the protruding units 36 b and the shape of the through holes 36a.

As shown in FIGS. 9 and 11, in each attachment unit 64, the through hole64 a and the tooth 60 a at the front among the plurality of teeth 60 aare aligned in the vertical direction.

The frontward protruding units 65 position in front of the to-be-engagedunits 10, respectively, and they protrude frontward than the attachmentunits 63 and 64.

The frontward protruding units 65 are to be inserted respectively in theconcave units 38 which are formed on the back surface of the front cover30, and are arranged so as to face the reinforcement ribs 38 a which arearranged at the outer edges of the concave units 38, respectively.

The locking member 11 engages with a to-be-engaged unit 10 to constitutethe main part of the front-back locking mechanism with the to-be-engagedunit 10. As shown in FIGS. 1, 3, 6 to 12, the locking member 11 includesa to-be-held unit 70, engaging units 71 and 71 and connecting units 72and 72.

The to-be-held unit 70 is a metallic shaft and is to be held by theaffixed-side member 4. As shown in FIGS. 6 and 7, the to-be-held unit 70is arranged at the back of the affixed-side member 4 and is held in astate being inserted in the holding unit 21 from the above, the holdingunit 21 being arranged on the back surface of the affixed-side member 4.

The to-be-held unit 70 is arranged in the spaces 62 between the firstprotruding units 60 and the second protruding units 61. The to-be-heldunit 70 is arranged above the engaging units 71 and 71.

The two ends of the to-be-held unit 70, there back surface sides, areinserted in the slits 31 f of the tip housing units 31 d of the backcover 31.

The engaging units 71 and 71 are metallic shafts, and they are arrangedto be parallel to the to-be-held unit 70 and rotate around theto-be-held unit 70, the to-be-held unit 70 being the shaft, and they arebiased toward the plurality of teeth 60 a to be engaged with any of theplurality of teeth 60 a. The engaging units 71 and 71 are arranged infront of the affixed-side member 4.

The engaging units 71 and 71 are arranged at the positions engaging withthe plurality of teeth 60 a by being biased by the biasing units 12. Asshown in FIG. 12, in a case where the engaging units 71 and 71 move inthe direction opposite to the biasing direction of the biasing units 12,the engaging units 71 and 71 are to move to the positions of the spaces62.

With respect to the engaging units 71 and 71, the tip parts (frontedges) thereof on the plurality of teeth 60 a sides are protruded insidethan the to-be-engaged units 10 and 10. However, the protruding lengthsare set so as not to reach to the X linkage mechanism.

The connecting units 72 and 72 are metallic shafts, and they connect theedges of the to-be-held unit 70 and the edges of the engaging units. Theconnecting units 72 and 72 are arranged on the left and right sides ofthe affixed-side member 4. That is, the locking member 11 is formed inan approximately C shape so as to go around the circumference of theaffixed-side member 4.

With respect to the connecting units 72 and 72, a cover member 73 whichcovers one connecting unit 72 and ends of the to-be-held unit 70 and theengaging unit 71 on the connecting unit 72 side is attached integrallyat the one connecting unit on the side where the rotary operation member13 is to be arranged. That is, the one connecting unit 72 includes thecover member 73.

As shown in FIG. 6, the cover member 73 of the connecting unit 72 abutsa side surface of the affixed-side member 4.

The cover member 73 of the embodiment covers one of the connecting units72. However, the cover member 73 may be configured as a member where oneend of the to-be-held unit 70 and one end of the engaging unit 71 are tobe attached.

The cover member 73 of the connecting unit 72 includes a projectingabutting unit 74 which projects toward the rotary operation member 13side and abuts the rotary operation member 13, the projecting abuttingunit 74 being arranged at the part of the cover member 73 correspondingto the position of the engaging unit 71.

The projecting abutting unit 74 is formed in a round shape so as tocorrespond to the movement of the rotary operation member 13.

The cover member 73 includes a escape unit 75 which avoids theinterference between the cover member 73 and the protruded unit 2 cwhich is arranged at one of the pillars 2 a.

This escape unit 75 is formed to have a concave shape at the position onthe affixed-side member 4 side surface of the cover member 73corresponding to the protruded unit 2 c.

The biasing units 12 bias the engaging units 71 and 71 of the lockingmember 11 toward the to-be-engaged units 10 side. As shown in FIGS. 1, 3and 8 to 12, coil-like tension springs are used in the embodiment.

With respect to each tension spring 12, the two ends thereof are hookunits 12 a and 12 a which are formed in a hook-like shape. One of thehook units 12 a and 12 a is hooked to an engaging unit 71 and the otheris hooked to a catch unit 28 b which is arranged at a lock holding unit28 of the affixed-side member 4. The tension springs 12 are respectivelyarranged between the engaging units 71 and the lock holding units 28.Further, a plurality of tension sprints 12 are arranged at both of theengaging units 71 and 71 of the locking member 11 and at both of thelock holding units 28 and 28 of the affixed-side member 4.

That is, the engaging units 71 and 71 are pulled toward the lock holdingunits 28 and 28 side by the tension springs 12 and 12. In such way, theengaging units 71 and 71 are in a state being biased toward theplurality of teeth 60 a . . . side.

The biasing units 12 of the embodiment are coil-like tension springs 12which are arranged between the engaging unit 71 and the lock holdingunits 28. However, this is not limitative in any way. For example, asshown in FIG. 14, a winding spring 12A having a tip 12Ab which extendstoward the front surface side from the back surface side of theaffixed-side member 4 may be used.

With respect to such winding springs 12A, the main bodies 12Aa are to bearranged on the back surface side of the affixed-side member 4 and arefixed there by being wounded around the to-be-held unit 70. The tipunits 12Ab go over the side surfaces of the affixed-side member 4 andare hooked to the engaging units 71. In such way, the engaging units 71can be engaged with the plurality of teeth 60 a of the to-be-engagedunits 10.

The rotary operation member 13 is made of resin. As shown in FIGS. 1, 3,4 and 6, for example, the rotary operation member 13 is held by themovable-side member 5 so as to rotate freely and operates the engagingunit 71 of the locking member 11. That is, the rotary operation member13 rotates in the direction to operate the engaging units 71 in thedirection which is opposite to the biasing direction of the tensionsprints 12 and to release the engaged state with the plurality of teeth61 a.

The rotary operation member 13 is arranged in the direction in which theengaging units 71 of the locking member 11 are biased by the tensionsprings 12.

The rotary operation member 13 includes a first operation unit 80, asecond operation unit 81 and a rotary shaft unit 82 which is the rotaryshaft. The first operation unit 80, the second operation unit 81 and therotary shaft unit 82 are formed integrally.

The rotary shaft unit 82 is formed in a column shape and is held by theupper abutting unit 33 a and the lower abutting unit 33 b of the holdingunit 33 abutting the outer circumference surface of the column shape.

The assembling direction of the rotary operation member 13 to theholding unit 33 is set so as to correspond to the rotary shaft directionof the rotary operation member 13 (that is, the length direction of therotary shaft unit 82). That is, the rotary operation member 13 isconfigured so as not to be pulled out easily in directions other thanthe direction which is opposite to the assembling direction (that is,the projection direction of the holding unit 33) in a state where therotary operation member 13 is held by the holding unit 33.

The rotary shaft unit 82 is arranged below the front-back lockingmechanism and is arranged above the up-down locking mechanism.

The first operation unit 80 is for operating the front-back lockingmechanism. The first operation unit 80 is formed so as to protrudetoward the affixed-side member 4 from the part of the outercircumference surface of the rotary shaft unit 82 which is within therange where the upper abutting unit 33 a and the lower abutting unit 33b do not abut each other. The tip of the first operation unit 80 in theprotruding direction is arranged below the cover member 73 of thelocking member 11 and the upper surface of the first operation unit 80is in contact with the projecting abutting unit 74.

The tip of the first operation unit 80 in the protruding direction isarranged below the rotary shaft unit 82. Therefore, when the firstoperation unit 80 is rotated upward with the rotary shaft unit 82 beingthe shaft, the cover member 73 can be moved upward.

The rotary operation member 13 includes concave units 83 and 83 in whichthe tips of the holding units 33 are to be inserted when the rotaryoperation member 13 rotates. That is, at the boundary part of the firstoperation unit 80 and the rotary shaft unit 82, the concave units 83 and83, in which the plurality of claw units 33 c and 33 c of the upperabutting unit 33 a of the holding unit 33 are inserted when the rotaryoperation member 13 rotates, are formed. Therefore, if the rotaryoperation unit 13 rotates upward, the claw units 33 c and 33 c areinserted in the concave units 83 and 83. Therefore, the rotationalmoving amount increases for that part.

The second operation unit 81 is for operating the up-down lockingmechanism and is formed so as to project downward from the approximatelycenter in the lower surface of the first operation unit 80. The tip ofthe second operation unit 81 in the projecting direction is arrangedbelow the up-down locking member 14 and the approximate center of thesecond operation unit 81 in the projecting direction is at substantiallythe same height as the up-down locking member 14.

With respect to the surface of the second operation unit 81 on theaffixed-side member 4 side, it is parted from the up-down locking member14 when the up-down locking mechanism is locked and it is in contactwith the up-down locking mechanism 14 when the up-down locking mechanismis unlocked. The surface of the second operation unit 81 which is theopposite to the surface on the affixed-side member 4 side is in contactwith the button 9 (after mentioned).

By adapting the above configuration, movement of the movable-side member5 in the front and back directions with respect to the affixed-sidemember 4 can be locked or unlocked at any of a plurality of positions,that is, at a position where the engaging unit 71 engages with any ofthe plurality of teeth 60 a.

(Up-Down Locking Mechanism)

The up-down locking mechanism is provided with respect to the pair ofpillars 2 a and 2 b. The up-down locking mechanism is to lock theaffixed-side member 4 at any of the plurality of positions in the up anddown directions with respect to the pair of pillars 2 a and 2 b.

The up-down locking mechanism includes a plurality of cutouts 15 . . .which are formed in at least one of the pillars 2 a and 2 b forming thepair, a pair of pillar holding units 4 a and 4 b, the up-down lockingmember 14 and the rotary operation member 13.

It is sufficient that the plurality of cutouts 15 are formed in at leastone of the pillars 2 a and 2 b forming the pair, the one being thepillar to which the up-down locking member 14 is provided. However,since the plurality of cutouts 15 are to be used in the mechanism forpreventing the pillars 2 a and 2 b from sliding out, the mechanism beingconfigured by the lock units 3 d and 3 d of the pair of holder unit 3and 3, in the embodiment, the plurality of cutouts 15 . . . are formedin both pillars 2 a and 2 b forming the pair.

As shown in FIGS. 1, 6 and 10, the plurality of cutouts 15 are formed ina multiple step manner along the length direction of the pillars 2 a and2 b forming the pair. The plurality of cutouts 15 . . . are formed onthe outer circumference surfaces of the pillars 2 a and 2 b forming thepair near the centers thereof.

As described above, the pillar holding units 4 a and 4 b forming thepair are for respectively holding the pillars 2 a and 2 b forming thepair. In such way, the affixed-side member 4 can move in the up and downdirections along the pair of pillars 2 a and 2 b.

The up-down moving range of the affixed-side member 4 is based on therange where the projecting units 2 c and 2 c provided at the pillars 2 aand 2 b forming the pair can slide along the slits 31 f and 31 f whichare formed on the sides of the affixed-side member 4.

The up-down locking member 14 is held by one of the lock holding units28 and 28 which are respectively formed at the pillar holding units 4 aand 4 b forming the pair, the one being the lock holding unit 28 towhich the rotary operation member 13 is arranged.

The up-down locking member 14 includes an engaging unit (not shown)which engages with a cutout 15 inside the lock holding unit 28 and abiasing member (not shown) which biases the engaging unit in thedirection engaging with the cutout 15.

If the up-down locking member 14 is operated so as to be pushed in tothe back of the lock holding unit 28, the engaging unit, which is notshown, parts from the cutout 15. If the up-down locking member 14 is notoperated as described above, the engaging unit, which is not shown, isto be in the state engaging with the cutout 15.

The rotary operation member 13 includes the second operation unit 81 foroperating the up-down locking member 14 as described above. On a sidesurface of the second operating member 81 that abuts the up-down lockingmember 14, a groove 84 which engages with the lower end of the up-downlocking member 14 when abutting the up-down locking member 14 is formed.

The first operation unit 80 and the second operation unit 81 areinterlinked to rotate. The second operation unit 81 can carry out theunlocking operation by the up-down locking mechanism at the same timewhen the first operation unit 80 carries out the unlocking operation ofthe front-back locking mechanism.

The length of the rotary operation member 13 in the front and backdirections is set to be the length according to the moving distance ofthe movable-side member 5. That is, the first operation unit 80 is to beabutted by the projecting abutting unit 74 at all parts along its lengthdirection. The second operation unit 81 is to be abutted by the button 9at all parts along its length direction, and all parts of the secondoperation unit 81 abut the up-down locking member 14. The rotary shaftunit 82 is to be held by the holding unit 33 along its length direction.

Since all parts of the second operation unit 81 along its lengthdirection are abutted by the button 9, the positional relation betweenthe rotary operation member 13 and the button 9 changes according tomoving of the movable-side member 5 in the front and back directions.However, the positional relation between the front cover 30 and the backcover 31 which are the movable-side member 5 and the button 9 does notchange.

By adopting the above described configuration, the affixed-side member 4can be locked or unlocked at any of the plurality of positions in the upand down directions with respect to the pair of pillars 2 a and 2 b,that is, at any of the positions where the plurality of cutouts 15 areformed.

The button 9 which is the operation unit 9 is to be attached to thebutton attachment unit 34 which is arranged on the sides of the frontcover 30 and the back cover 31 as described above, and the button 9abuts the rotary operation member 13. By the button 9 being pushed in tothe inner space unit, the rotary operation member 13 can be operated.

The button 9 includes a button main body 90 and a cylindrical unit 91.

The button main body 90 is inserted in the cylindrical unit 91 and canfreely move forward and backward along the cylindrical unit 91. Thebutton main body 90 includes a surface unit 90 a and a protruding unit90 b.

The surface unit 90 a is the part where a person operating the button 9directly touches.

The protruding unit 90 b is arranged at the end part of the button mainbody 90 on the inner space unit side thereof and is the part that abutsthe rotary operation member 13. In particular, the protruding unit 90 babuts the lower end (the end in the projecting direction) of the secondoperation unit 81 of the rotary operation unit 13.

The cylindrical unit 91 is held by being inserted in the button holdingunit 34 c of the button attaching unit 34. The cylindrical unit 91includes a plurality of engaging claw units 91 a which engage with thebutton holding unit 34 c when the cylindrical unit 91 is inserted in thebutton holding unit 34 c.

By adapting the configuration as described above, the rotary operationmember 13 can rotate upward with the rotary shaft unit 82 being theshaft. With this operation, the locking member 11 can be operated by thefirst operation unit 80 and the up-down locking member 14 can beoperated by the second operation unit 81.

Next, operation of the headrest 1 having the above describedconfiguration will be described.

The operation of the headrest 1 includes the operation of themovable-side member 5 moving forward in the direction parting from theaffixed-side member 4 and moving backward so as to return from forwardlyparted state. Further, the operation of the headrest 1 includes theoperation of the affixed-side member 4 including the pair of pillarholding units 4 a and 4 b moving in the up and down directions along thepair of pillars 2 a and 2 b.

First, operation of the movable-side member 5 will be described.

FIGS. 8 and 9 show the state where the movable-side member 5 is near theaffixed-side member 4. That is, the movable-side member 5 is in thestate returned to the back although not totally to the very back. Whenthe button 9 is not being operated, the engaging unit 71 is in the stateengaging with the tooth 60 a of the to-be-engaged unit 10, and themoving of the movable-side member 5 in the front and back directions islocked.

Starting from such state, in order to move the movable-side member 5 soas to part forwardly from the affixed-side member 4, first, the button 9is pushed in to make the rotary operation member 13 rotate to the Xlinkage mechanism side. With such operating, the first operation unit 80is rotated upward and the engaging unit 71 provided with the covermember 73 is pushed upward.

In such way, since the engaging units 71 part from the teeth 60 a of theto-be-engaged units 10, the locking of the movement of the movable-sidemember 5 in the front and back directions by the locking member 11 canbe unlocked.

Then, while maintaining the state where the engaging units 71 beingpushed up, the movable-side member 5 is moved in the direction partingforwardly from the affixed-side member 4.

At this time, the to-be engaged units 10 move forward with the rotaryoperation of the inner-side link member 6 and the outer-side link member7. At this time, the connecting member S of the inner-side link member 6and the connecting member S of the outer-side link member 7 move upwardalong the elongated holes 26 a and the elongated holes 36 a of theplurality of lower supporting units 26 and 36.

When the operating of the button 9 is stopped at a desired position, theengaging units 71 return to the original positions by being biasedtoward the plurality of teeth 60 a according to the biasing force of thetension springs 12 and engage with any of the plurality of teeth 60 a.In such way, as shown in FIGS. 10 and 11, the movable-side member 5 canbe moved to the direction parting forwardly from the affixed-side member4 to lock the movement of the movable-side member 5 at a desiredposition.

At this time, there is a case where the engaging units 71 do not fit inthe dents between the teeth 60 a and 60 a which are next to each otherand come into contact with the tips near the teeth 60 a. In such case,by the movable-side member 5 being moved in either front or backdirection without operating the button 9, the engaging units 71 fall inthe nearest dints and the movable-side member 5 can be locked.

Similarly, when the movable-side member 5 being returned to the back,first, the button 9 is pushed in and the cover member 73 is operated tounlock the locking by the engaging units 71.

Thereafter, it is sufficient to return the movable-side member 5 to theback and stop the operation of the button 9 at a desired position. Atthis time, the X linkage mechanism operates reversely from when themovable-side member 5 is moved to the front.

As described above, the movable-side member 5 can be moved in the frontand back directions and a step-wise position adjustment according to thearrangement of the plurality of teeth 60 a of the to-be-engaged units 10can be realized. That is, the position adjustment of the headrest 1 inthe front and back directions can be carried out in a step-wise manner.

Next, upward and downward operation of the affixed-side member 4including the pair of pillar holding unit 4 a and 4 b will be described.

FIGS. 8 and 9 shows the state where the pair of pillar holding unit 4 aand 4 b are positioned at the downward side of the pair of pillars 2 aand 2 b. When the button 9 is not being operated, the engaging unit ofthe up-down locking member 14 is in the state being engaged with onecutout 15 at the lower side of the pillar 2 a, and the movement of thepair of pillar holding units 4 a and 4 b in the up and down directionsis locked.

Starting from such state, in order to move the pair of pillar holdingunits 4 a and 4 b upward along the pair of pillars 2 a and 2 b, first,the button 9 is pushed inside to make the rotary operation member 13rotate toward the X linkage mechanism side. With this operation, thesecond operation unit 81 is rotated toward the X linkage mechanism sideto push in the up-down locking member 14 to the back of the lock holdingunits 28, and the engaging units which are not shown are moved to theback of the lock holding units 28.

In such way, the engaging unit of the up-down locking member 14 partsfrom a cutout 15 of the pillar 2 a. Therefore, the locking of the movingof the pair of pillar holding units 4 a and 4 b in the up and downdirections by the engaging unit of the up-down locking member 14 can beunlocked.

Then, while maintaining the state where the engaging unit of the up-downlocking member 14 is moved to the back of the lock holding unit 28, thepair of pillar holding units 4 a and 4 b is moved upward along the pairof pillars 2 a and 2 b and then the affixed-state member 4 is movedupward along the pair of pillars 2 a and 2 b.

At this time, the movable-side member 5, and the X linkage mechanism andthe like move upward with the moving of the affixed-side member 4.

When the operation of the button 9 is stopped at a desired position, theengaging unit of the up-down locking member 14 returns to the originalposition due to the biasing force of the biasing member which is notshown, and engages with one cutout 15 at the upper side of the pillar 2a. In such way, as shown in FIGS. 10 and 11, the pair of pillar holdingunits 4 a and 4 b are moved upward along the pair of pillars 2 a and 2 band the movement of the pair of pillar holding units 4 a and 4 b can belocked at a desired position.

At this time, there is a case where the engaging unit of the up-downlocking member 14 does not fit in the dent between the cutouts 15 and 15which are next to each other in the up and down directions and contactsthe outer circumference of the pillar 2 a. In such case, by moving thepair of pillar holding unit 4 a and 4 b in either up or down directionwithout operating the button 9, the engaging unit falls in the nearestcutout 15 and the pair of pillar holding units 4 a and 4 b can belocked.

Similarly, when moving the pair of pillar holding units 4 a and 4 bdownward, first, the button 9 is pushed in to operate the secondoperation unit 81 so that the locking by the engaging unit of theup-down locking member 14 is unlocked.

Thereafter, the pair of pillar holding units 4 a and 4 b and theaffixed-side member 4 are moved downward and it is sufficient to stopthe operation of the button 9 at a desired position. At this time, themovable-side member 5, the X linkage mechanism and the like also movedownward with the moving of the pair of pillar holding units 4 a and 4b.

As described above, the pair of pillar holding units 4 a and 4 b can bemoved in the up and down directions and a step-wise position adjustmentaccording to the plurality of cutouts 15 . . . of the pillar 2 a can berealized. That is, the position adjustment of the headrest 1 in the upand down directions can be carried out in a step-wise manner.

According to the embodiment, the front-back positional adjustment of themovable-side member 5 using the to-be-engaged units 10 and supporting ofthe heat by the to-be-engaged units 10 at the time collision arecompatible. Therefore, the level of comfort and security of the seatwhen a passenger sits thereon can be improved.

Since the plurality of to-be-engaged units 10 and 10 are arranged at aplurality of parts having the moving mechanism therebetween, operationof the moving mechanism and the front-back locking mechanism can becarried out in a good balance. Further, since the head can be supportedby the plurality of to-be-engaged units 10 and 10, the level of securitycan be improved.

Since the connecting members S are used to connect the to-be-engagesunits 10, the link 6 (7) and the supporting units 35 (36) and used asrotary shafts, the number of parts needed can be reduced due to sharingthe parts.

Even if the parts to be connected increase, they can be connected by theconnecting members S. Therefore, the effect of reduction in the numberof parts due to sharing can be improved even more.

Therefore, such configuration can preferably respond to the request toreduce the number of parts by sharing the parts.

Moreover, the length in the up and down directions of the part near theupper end of the elongated hole 64 a of one of the attachment units 64can be made longer for the part corresponding to the very front teeth 60a. Therefore, rigidity of one of the attachment units 64 can beimproved.

Therefore, such configuration can preferably respond to the request toimprove the rigidity of one of the attachment units 64 and theto-be-engaged units 10.

By forming at least one of the plurality of reinforcement units 53 . . .of the link member 7 (6) in the honeycomb structure, the link member 7(6) can be lightened and reinforced so as not to bend easily.

Therefore, such configuration can preferably respond to the request tomake the link member 7 (6) lighter and to reinforce the link member 7(6) so as not to bend easily.

Interference between the reinforcement rib 37 of the front cover 30 andthe front end part of the link member 6 (7) can be prevented, andrigidity of the front cover 30 can be improved by the reinforcement rib37.

Therefore, such configuration can preferably respond to the request toprevent interference between the reinforcement rib 37 and the front endpart of the link member 6 (7) and to improve rigidity of the front cover30.

The upper end parts of the pair of pillar holding units 4 a and 4 b canbe connected by the connector 4 d. Therefore, the connecting conditionof the pillar holding units 4 a and 4 b forming the pair can be improvedand rigidity of the affixed-side member 4 can be improved.

Therefore, such configuration can preferably respond to the request toimprove the connecting condition of the pillar holding units 4 a and 4 bforming the pair and to improve the rigidity of the affixed-side member4. In the technique of Patent Document 1, the back-side fixated rotaryshaft which is the rotary shaft of the arms constituting the link memberis also used as the member connecting the upper end parts of the leftand right side surfaces. Therefore, there has been a desire to improvethe rigidity. In view of this, the affixed-side member 4 of theembodiment is preferable since the rigidity is improved by the connector4 d.

Since the moving mechanism can be housed in the concave unit 22, thelimited space between the affixed-side member 4 and the movable-sidemember 5 can be used efficiently, and the headrest 1 can be formed in acompact manner.

Therefore, such configuration can preferably respond to the request toform the headrest 1 in a compact manner.

The projecting tips of the to-be-engaged units 10 which are inserted inthe through holes 23 a and 23 b are held by the affixed-side member 4 inwhich the through holes 23 a and 23 b are formed. Further, since theto-be-engaged units 10 can be supported by the walls 24 a and 24 b whichface the to-be-engaged units 10, stability of the movable-side member 5at the time of front-back positional adjustment can be improved.

Therefore, such configuration can preferably respond to the request toimprove the stability of the movable-side member 5 at the time offront-back positional adjustment.

INDUSTRIAL APPLICABILITY

The headrest of the embodiment can be applied to a headrest whichreceives the head of a passenger who sits on a seat.

REFERENCE SIGN LIST

-   1 headrest-   2 a pillar-   2 b pillar-   4 affixed-side member-   4 a pillar holding unit-   4 b pillar holding unit-   4 c back side connector-   4 d connector-   5 movable-side member-   6 first link member-   7 second link member-   8 cross connection unit-   9 operation unit-   10 to-be-engaged unit-   11 locking member-   12 biasing unit-   13 rotary operation member-   14 up-down locking member-   15 cutout-   20 pillar inserting hole-   23 a through hole-   23 b through hole-   24 a wall-   24 b wall-   25 supporting unit-   25 a through hole-   26 supporting unit-   26 a through hole-   27 reinforcement unit-   28 lock holding unit-   28 a opening-   28 b catch unit-   30 front cover-   30 b surrounding unit-   31 back cover-   31 b surrounding unit-   33 holding unit-   35 supporting unit-   35 a through hole-   35 b protruding unit-   36 supporting unit-   36 a through hole-   36 b protruding unit-   40 first arm-   41 second arm-   42 connection-   50 side wall unit-   51 inside unit-   52 connection-   53 reinforcement unit-   60 first protruding unit-   60 a plurality of teeth-   61 second protruding unit-   62 space-   63 attachment unit-   63 a through hole-   64 attachment unit-   64 a through hole-   70 to-be-held unit-   71 engaging unit-   72 connecting unit-   73 cover member-   74 protruding abutting unit-   75 escape unit-   80 first operation unit-   81 second operation unit-   82 rotary shaft unit-   83 concave unit-   90 button main body-   90 b protruding unit

The invention claimed is:
 1. A headrest, comprising: an affixed-sidemember which is arranged at a headrest pillar; a movable-side memberwhich is connected to the affixed-side member via a moving mechanism andwhich moves in front and back directions with respect to theaffixed-side member; and a front-back locking mechanism which locks andunlocks movement of the movable-side member in the front and backdirections with respect to the affixed-side member, the front-backlocking mechanism including: a to-be-engaged unit; a lock member whichengages with the to-be-engaged unit; a biasing unit which biases thelock member in a biasing direction toward the to-be-engaged unit; arotary operation member which operates the lock member and which is heldby the movable-side member so as to rotate freely; and a button whichoperates the rotary operation member and which is provided on themovable-side member, wherein, when operating the lock member, the rotaryoperation member rotates in a direction which is opposite to the biasingdirection to release an engaging state of the lock member with theto-be-engaged unit, a length of the rotary operation member in the frontand back directions is set to a length according to a moving distance ofthe movable-side member, and the movable-side member includes a coverwhich is provided with a ring-shaped button holding unit which holds thebutton.
 2. The headrest according to claim 1, wherein a plurality of theto-be-engaged units are provided, and the plurality of the to-be-engagedunits are arranged at position so that the moving mechanism is to bearranged therebetween.
 3. The headrest according to claim 1, wherein themoving mechanism is formed in a linkage mechanism, the cover includessupporting units which rotatably support link members which constitutethe linkage mechanism, and connecting members, which rotatably connectend parts of the link members to the supporting units, are provided soas to penetrate the to-be-engaged unit, the link members and thesupporting units.
 4. The headrest according to claim 3, wherein thelinkage mechanism is a X linkage mechanism including a first link memberand a second link member which are rotably connected via a center crossconnection unit, and the supporting units of the cover are arranged onboth sides of the cover in up and down directions, a front end of thefirst link member and a front end of the second link member arerotatably supported by the upper and lower supporting units, and theconnecting members are provided so as to respectively penetrate thesupporting units.
 5. The headrest according to claim 4, wherein throughholes in which the connecting members go through are respectively formedat the upper and lower supporting units, one of the through holes of theupper and lower supporting units is an elongated hole which is elongatedin the up and down directions, the to-be-engaged unit includes: aplurality of teeth which are arranged in front and back directions; andupper and lower attaching units which are attached to the cover, throughholes in which the connecting members go through being formed in theupper and lower attaching units, one of the through holes of the upperand lower attachment units is an elongated hole which is elongated inthe up and down directions, and the one of the through holes of theattaching units and a tooth at very front among the plurality of teethalign in a vertical direction.
 6. The headrest according to claim 3,wherein the link members include a plurality of reinforcement unitsarranged at a plurality of parts of the link members, and at least oneof the plurality of reinforcement units is formed in a honeycombstructure.
 7. The headrest according to claim 3, wherein the coverincludes a reinforcement rib which is arranged on a back surface of thecover, and the reinforcement rib and the front end parts of the linkmembers are arranged on left and right sides of each other.
 8. Theheadrest according to claim 1, wherein the headrest pillar includes apair of pillars, the affixed-side member includes: a pair of pillarholding units which are arranged on both side end parts of theaffixed-side member and which respectively hold the pillars of theheadrest pillar forming the pair; and a connector which connects betweenthe upper ends of the pillar holding units forming the pair.
 9. Theheadrest according to claim 8, wherein a part of the affixed-side memberwhich is surrounded by the pillar holding units forming the pair and theconnector is a concave unit, and when the affixed-side member and themovable-side member are close to each other, the moving mechanism is tobe housed in the concave unit.
 10. The headrest according to claim 1,wherein the to-be-engaged unit is projected toward the affixed-sidemember from the back surface of the cover, a through hole is formed inthe affixed-side member at a position corresponding to the to-be-engagedunit, the to-be-engaged unit being inserted in the through hole, and awall which faces the to-be-engaged unit is provided at a circumferenceof the through hole.